I need help trying to generate a 2D array (20x20 grid) with O's and X's. I'm later going to replace these with images to build somewhat of a map/grid. But I just need to fill them in with characters and not integers.

I don't know if that formatted right because the code thing is being weird for me, but if I have this right. How exactly do I print it out for when I run it?
I can't test it because I don't know how to print it out :/
But I feel like I have it wrong anyway.

EDIT
Then I also need to know how to swap the multidimensional array vertically... still keeping the same values/grid setup, but basically just reflecting it vertically. Not horizontally though..